The present invention relates to a pressurized water drain for a pressurized cooling pipe for directly and intensively cooling rolling stock heated by rolling heat. Liquid cooling medium is applied in a parallel flow through nozzle heads onto the rolling stock and discharged once again over a storage chamber. Cooling pipes of this type are suitable particularly for cooling rolled steel from the rolling heat.
Two constructions of cooling pipes for the direct, intensive cooling of rolling stock are well known: the parallel flow/countercurrent flow cooling pipe for rolling stock of thicker dimensions having low final rolling speeds and the parallel flow cooling pipe for rolling stock of thin dimensions and high final rolling speeds.
The parallel flow cooling pipe, used for thin-walled rolling stock and high final rolling speeds, has undisputed, important advantages for direct, intensive cooling. However, in the case of the known technical constructions, the discharge of the liquid is inadequate, so that the final rolling speeds, practically attainable with previously known parallel flow cooling pipes, are limited.
For rolling stock of thicker dimensions, for which relatively large amounts of water are required for the cooling, the previously used parallel flow cooling pipes are less suitable, since the water flows at the end of the cooling part cannot be controlled adequately. It is well known that the pressurized water, which emerges at the end of the cooling pipe into the rolling heat, in all cases leads to a braking effect on the roll line, regardless of whether the emerging cooling water is dammed up before a subsequent cooling pipe or loses its velocity at the end of the cooling segment. Moreover, the cooling water emerging at the ends of the cooling pipe leads to an undefined cooling, as a result of which the quality of the rolling stock treated therewith is reduced. In order to counteract the emergence of the cooling water at the end of the parallel flow cooling pipe, it is well known to have storage chambers disposed at the end of the cooling pipe. The storage chambers are then followed by a short piece of a countercurrent cooling system which, in the most advantageous case, consists of only one countercurrent head acted upon by so much cooling water that the emergence of the cooling water from the end of the cooling pipe is barely prevented. However, braking forces are produced with this measure, which are already so high, that a buckling of thin roll lines can occur at high final rolling speeds.
The EP 13 230 discloses a pressurized cooling pipe having deflection chambers which have several apertures, or rings, for the passage of the rolling stock, at which either guide funnels or deflections cones are disposed. In the case of this known solution, a stripping effect is achieved largely by the effect that the cross section of a jet is reduced by the apertures and the stripped water is diverted. At the end of the construction a stripping pipe is provided which is perpendicular to the direction in which the rolling stock is moving and is supplied with a liquid or gaseous medium which, as a separate secondary stream, directed on the roll line perpendicular to the direction of movement of the rolling stock, strips the remainder of the cooling water. This known construction operates in such a manner that the cooling water is deflected, dammed up and then partially stripped by the orifices or rings disposed in the deflection chambers. At the same time, in a direction countercurrent to the roll line, the cooling medium is dammed up and, consequently a braking effect is exerted on the rolling stock. Accordingly, large amounts of cooling water cannot be deflected from the rolling direction. Furthermore, due to the free arrangement of the outlet openings of the stripping pipe, only uncontrolled stripping of the coolant residues still adhering to the roll line can be attained.
In accordance with EP 64 771, cooling water is deflected by a deflection chamber connected in series with a storage chamber and baffle plates, which are closed off in the upward direction and are disposed in front of the guiding funnels, feed pipes for a liquid and/or gaseous stripping medium ending in the baffle plates. The disadvantage of this construction is that the cooling water and the steam, formed by the cooling, must be discharged from the storage chamber and from the deflection chamber.